1. Field of the Invention
The present invention relates to a battery-driven type display device for switchingly displaying each page of contents to be displayed onto a storage-type display unit, that is, a display unit capable of holding contents which has been displayed thereon even if power supply is stopped.
2. Description of the Related Art
As a display device of this kind, there has been known a display device for electronic books which switchingly displays each page of contents, such as a book, separated in predetermined pages onto a storage-type display unit, such as a cholesteric liquid crystal or electrophoretic display unit, and enables a user to browse the contents, for example, as described in JP2003-233443A.
For example, a mobile telephone is also known which immediately displays a remaining battery level on its display to prompt exchange or charging of the battery. A notebook computer is also known which displays available time corresponding to a remaining battery level on its display.
In the case of a display device which switchingly displays each page of contents on a storage-type display unit and displays a remaining battery level, a display device realized by combination of the above prior-art techniques, even if a low remaining battery level is displayed while a user is browsing contents, it is difficult for him to determine whether or not he can finish reading remaining pages with the current low remaining battery level.
Furthermore, since the display device using a storage-type display unit consumes power only when switching display is performed, it is impossible to specify available time corresponding to a remaining battery level.
The present invention has been made in consideration of the unsolved problems of the prior-art techniques, and its object is to provide a display device which makes a remaining battery level notification appropriate for a storage-type display unit.